Almost three years ago, I won a DSLR package from Scott Bourne. (My blogpost about that happy event can be found here.) Included in that package is the Canon 5D Mark II, which I still absolutely love, and the Canon EF 24-105 f/4L IS USM lens.
This lens has been a constant companion and is something that I cannot live without. I can live without a telephoto lens, or a macro lens, but not this. For me, the flexibility of this lens cannot be surpassed - it can go from a wide angle, especially with a full-frame sensor, to a moderate telephoto; the image stabilization enables me to do low-light photography up to 1/15 of a second and the lens is relatively light and does not occupy such a large space in my camera bag.
This lens is not a completely "waterproof" lens but I don't mind photographing with it during a slight shower, or near a fountain. But of course, the lens is more "weather-sealed" when paired with a weather-sealed DSLR body, like the Canon 7D.
I love the pictures I've made with this lens - for me, the sharpness of this lens can be compared to that of a prime lens. The colors are true and there is not much fringing nor aberrations - if at all. Well, as far as I can tell from my own photos...
The lens is well-made, as to be expected from Canon. Also, the fact that this is an "L" lens means that its quality is beyond that of an ordinary lens. Well, it also means that there is a hefty price tag that comes along with this lens...
However, if I am forced to have only one lens, then this lens would be it. The quality of the lens, the very versatile zoom range, and the quality of the photos produced make this Canon a must-have.
It is HIGHLY RECOMMENDED!
So get yours here!
If you have an APS-C DSLR like the Canon Rebels, then another good option is the Canon EF-S 15-85 IS USM lens. It has almost the same range (with the 1.6 factor) and it is priced lower than the 24-105. You cannot go wrong with either lens. But take note: you can use the EF lens on any DSLR but you cannot use the EF-S lens on full-frame cameras.
Gear used to make this post: